[R-390] SAQ in CT

[Jay Rusgrove]

Bill

There could be any number of sources of the noise. One big problem at LF is electrical noise
generated in the house which is conducted out the feedline to the antenna and then returns to the
receiver. This can be greatly reduced or eliminated with a ferrite transformer with primary and
secondary windings on opposite sides of the core (not bifilar wound). I use 46 turns for both the
primary and secondary on an FT-114-77 cores and keep the turns separated about a quarter inch.

This fix can't be used with an active antenna that must be supplied voltage via the coax. At this
location I'm unable to use active antennas (both loops and e probes) at LF for that reason -
although I can use them at other locations which are away from electrical noise sources.

The HP 3586C (and maybe the B as well) has a bfo pitch of 1850 Hz and is not adjustable. That means
you would have to tune the receiver to 18450 to get a beat note of 600 Hz when receiving 17200. The
receiver must be set to 3100 Hz bandwidth. Narrow band filtering can then be done with an external
audio filter or done in software. Despite this complexity in setup it makes an excellent receiver.

Jay W1VD

----- Original Message ----- 
From: "bill riches" <bill.riches at verizon.net>
To: "'Jay Rusgrove'" <JRusgrove at comcast.net>; <r-390 at mailman.qth.net>
Sent: Monday, December 24, 2007 11:56 AM
Subject: RE: [R-390] SAQ in CT


> Good Job Jay,
>
> I could not hear it - using 3586b, wellbrook loop and a K9AY loop.  When I
> have the 3586 tuned to 17.2, noise demod, entry fx = carrier, upper side
> band I am receiving a buzz saw with a sig strength of - 67 dbm on the
> Wellbrook. It zero beats about 18.0 khz.  Any idea where this racket is
> coming from. I get a 15 db null at 120/300 degrees.
>
> 73,
>
> Bill, WA2DVU
> Cape May, NJ
>
>
> 12/24/07
>
> Good reception of SAQ this morning. Signals were at their best during the
> pre-session tuneup, unfortunately IDs were few and far between. A clip of
> the pre-session with alternator coming up to frequency:
>
>  http://www.w1vd.com/SAQ122407A1A.wav
>
> ID at end of first session:
>
> http://www.w1vd.com/SAQ122407A1B.wav
>
> Conditions:
>
> 35 F Clear, low static levels
> Antenna: 14 turn 10' Octoloop
> Receiver: HP3586C SLM
> Filtering: Cooledit
> Report: ~439
>
> Jay Rusgrove W1VD
> Burlington CT USA
>
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